Electronic counting



5 A. E. JOEL, JR., ETAL 2,493,081

ELECTRONIC COUNTING Filed Dec. 29, 1944 F IG, 4

- A.'.JOEL,JR. WVENTORS' ROSOFFEL By v ATTORNEY l atenteri fab. 21

UNITED STATES PATENT oFFiCii 2,498,081 ELECTRONIC COUNTING Amos E. Joel, Jr., New York, and Robert 0. Sdffel, Hastings on Hudson, N. Y., assignors to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application December 29, 1944, Serial No. 570,440

9 Claims.

This invention relates to arrangements used for the automatic counting of electrical impulses and the like which heretofore has been accomplished by what are known as vacuum or gasdischarge tube counting rings, heretofore described in numerous patents and in technical literature, as, for example, the book Electrical Counting, by W. P. Lewis, published by Cambridge University Press (1942) More particularly the invention relates to the use of cathode-ray tubes having a plurality of discrete target anodes, arranged in one or more substantially straight rows, as a substitute for tube ring circuits of the prior art, whereby a considerable economy can be effected due to the reduction in apparatus and complexity of arrangements.

An object of the invention is to cause the electron beam of a cathode-ray tube, of the character described, to advance step-by-s'tep at the frequency of an applied wave overall the target rows and to cyclically repeat this operation during the application of said wave.

A'feature of the invention whereby the foregoing object is attained resides in means, including a predetermined one of the targets of each row, responsive to said beam impinging thereon to return said beam to the first target of the row and repeat the cycle in the case of single row tubes or to return the beam to the first target of the next row and soon in the case of tubes havv ing a plurality of rows.

' In the case where a plurality of tubes are required, a further feature resides in means responsive to the beam of'the first tube impinging v on a predetermined target thereof to extinguish that beam and initiate a beam in the next tube, which beam will then be deflected in a similar manner as before across its corresponding targets.

.A further feature of the invention resides in employing a cathode-ray tube having a. plurality of parallel rows of targets and means for deflecting the beam so that it will be successively stepped across each row in turn.

The invention will be understood from the following description when read in connection with the accompanying drawings:

Fig. 1 of which shows a cathode-ray tube hav-' ing a single row of target anodes;

Fig. 2 shows a pair of cathode ray tubes each having a single row of target anodes together with means for disabling each tube as soon as its beam; reaches the last target, for conditioningthe other; tube for a subsequent operation, and repe'atingthe cycle; 1 {l Fig. 3 shows a tube having a plurality of parallel rows of target anodes (two in the drawing) to ether with means for successively deflecting the beam from row to row; and

Fig. 4 shows a so-called staircase sweep circuit for controlling the step-by-step beam deflection of the cathode ray tubes shown in any of the first three figures.

The operation of the arrangement of Figs. 1 and 4 will first be described:

Referring to Fig. 1 of the drawing, a cathoderay tube CR1 has been shown which is provided: with the usual filament connected to a suitable source of current for the production of an electron beam through the tube, which beam is employed to control a plurality of work circuits connected to target anodes indicated collectively by the reference character I located in the end of the tube which will be referred to hereinafter. A control anode 2 is also provided to control and concentrate the electron beam in a well-known manner for the purpose of controlling the deflection of the beam so that it will impinge on the target anode in a desired manner. A pair of de-' fiecting plates 3 are provided and so positioned within the tube as to cause the desired beam defiection when a predetermined potential exists between them. For the purpose of applying potential to the deflecting plates 3 to cause the beam to be deflected so that it will successively impinge on the individual target anodes l, for example from top to bottom a so-called staircase sweep circuit, shown in Fig. 4, is provided which comprises a double circuit rectifier tube 4 having two anodes and two cathodes contained in a single envelope, although two single tubes could obviously be employed, and also four thermionic vacuum tubes 5, 6, I and B, the circuits of which are so arranged that when a predetermined source of potential is applied thereto, a predeter mined maximum potential is applied over a deflec-j tion conductor 9 to the deflection plates 3 of the cathode-ray tube of Fig. 1 and, when successive negative control impulses are applied to the sweep circuitover. the input conductor ill, the potential on the defiecting plate of the cathode-ray tube is progress'ivelyrcduced in substantially equal steps to cause the cathode beam to move downward target Ito: target until the last; or controlisfrea'ched whereupon the sweep circuitre'cy ,thereby'rai'sing the potential of the de-. fleeting plates 3 to the original maximum value to sweep the beam back to its top or starting target: from which point the beam continues to again 3 move across the targets under control of the incoming pulses.

When the system is energized by connecting battery thereto, thermionic vacuum tubes 5, 6, 1 and 8, immediately start to conduct plate current and a potential is built up across the cathode resistance ll, of tube which is applied across the deflecting plates 3'of cathode-ray-tube-CRI sufiicient to deflect the cathode beam to the extreme top of the row of target anodes. Tube .6

also conducts at this time and charges thelarge.

capacity condenser l2 connected to its cathode. Further tubes 1 and 8 whichconstituteawell known arrangement having. certain of the. characteristics of a flip-flop circuit and other characteristics of a multivibrator circuit, each start to conduct but due to the constants ofthe circuit;

connections and the negative bias on the grid of 1, the plate current in 8 builds up faster than that of l and consequently the drop across the anode resistance of "8. applies an addedznegative bias to the grid of .7, thereby decreasingthe current therein until :apoint is reached-when 1 is blocked and 8 is passing-maximum current.- At this pointthe drop across theanodeiresistance of 8= applies vav sufficient negative potential to the grid of to block this tube which however, has

been conducting for a sufiicient interval to charge condenser I2.- Tubes 5 and 8 are now conducting, condenser I2 is fullychargedand the potential'drop across resistance II in thecathodecircuit of 5ris applied across deflecting plate 3 of the cathode-ray tube CRI which holds the beam to the-upper target ,of the row. If .now asuccession of alternate negative and positiveimpulses are transmittedtover the control conductor. [0,. the

first negative impulse causes the transfer of a;

small, incrementof charge on condenser [2 to the small capacity condenser I3 'in the control lead thereby decreasing the positivebias on the grid'of tube 5 by that amount and decreasing its plate-current accordingly which in turn decreases the potential across the cathode resistance, II to lower the. potential applied across deflecting, plates 3:01 thecathode-ray tube thereby causing the beam to be deflected -downwardthrougha small angle to impinge. on the second-anodepf the raw.

Whenthe succeeding positiveimpulseis transmitted over the control conductor In the condenser IB is discharged through resistancej i; the lefthand-discharge gap. of rectifier tube '4 and resistance Ilto ground thereby establishing. a, conditionwhBrby-thenext negative pulse will extract another small increment of potential from condenser l2 and transferv ittodischarge condenser l3 as before. Succeeding pulses of alternate negative and positive potentialcause thebeam of tube CRI to be deflected stepI-by -Step across the row of target anodes until it impinges on the lastor bottom targetof the row, whereupon .a negative impulse is transmitte'dover'the recycling conductor I5 to the gridof -tube 8 thereby momentarily blockingits plate circuit and 'raisingthe potential'on thegridsof tubes li and'l and permitting them toconduct;-whereupon condenser l2 -receives a renewal charge-dueto the plate current flowing in tube 6* and r the. potential on the grid of tube 5 1s raised to increase the currentflowing in its cathode iresistance. I I, whereupon the potential on the deflecting plates of the cathode-ray tube isrestored to the original high value and the beam is immediatelydeiiected back -to.= impingecon the. first :or upper target of the row As soon-as theibeam leaves the; bottom tinues to step across the row of targets and snap back to the starting position in response to the incoming pulses.

The target anodes of tube CRI can be connected-to control any desired work devices, as for example, electronic tubes indicated by the reference character 5 6,-Fig. 1.

Referring to Fig. 2, in conjunction with Fig. 4, it may be desired to employ two or more single row cathode-ray tubes of the type shown in Fig. 1 for the purpose of controlling a larger number of work devices than can be accumulated by a single tube In such a case an arrangement as shown ;in Fig. 2 can be used which-shows apair; of single row tubes CR2 and CR2 together with, thermionic tube means -.for alternately enabling. one or the other of the cathode-ray tubes; for. beamdeflection, and for disabling the otherin: response to the beam of'anenabled tube im pinging on the Iasttarget of-therow. In this; case, as in Fig. l, the-beam of an enabled tubea is deflected under control of the sweep circuit shown; in Fig.4.

When potential is applied :to a-systern in ac-- cordance WithFig's. 2 and 4, vacuum tubell quickly reaches its conductive condition-thereby blocking tube, l8 by placing: a negative potential? on its grid due to the drop across the plate circui-t resistance'of tube H. Due to the high positive potentialon the plateof blocked tube. 18,; which potential is applied over conductor E9 to, the control anode 2n of'cathode-ray tube CR2, this tube is enabled, and due to the .lowpotem tial on the plate of conducting tube ll, which isapplied over conductor 2! to the control anode 22, of tube CR2, this tube is disabled. Also,v when potential is applied tubes 5 and 8 .ofiFig; 4, as previously described,'--assume a steadyfcon-l ducting condition and tube fi conducts fora n in-v teryal sufiicient to charge condenser l2. The.

, drop across cathode-resistance llof tube 5 is,ap-,.

plied over conductor 9 to the deflecting plateswofboth cathode-ray tubes CR2 and CR2, but .asthev control anede 22 of tube CR2 is negative dueto the fact that tube I1, is conducting, the tube CR2 isdisabled, i. 'e., blocked.- Due to theposi, tive potential on the controlanodeiil of CR2 this tube is enabledand the high, potential, on its deflecting platev causesitsv beam to .be.-d e.. fiected and impinged on the extremei-uppertar; get 'of the row. As salternatenegative and -positive pulses are received over COndLlQtOLlom hQ potential across thedeflecting plates of 032 is, reduced stepeby step therebycausing. thegbeain of this tube to move downward ;o-,ver thectarget row until it impinges on its lowermost tar-get whereupon the grid of tube lliis driven .negatiye. by a sufficient amount .to. s Qp-current"flow inits plate circuit thereby raising the. potential oL-its anode which potential is applied, ovenconductor; 2| to .the control anode 22. of cathode-ray tube CR2 thus enabling it. This increased poten tial is also applied to the grid ottube .18, which, immediately starts to conduct thereby decreas; in it pl te-p tent al hi h) a plie e r 91 ductor l9 to the control anode 20 of tubeCRZ;

amperdisables this tube. on the plate of tube l8 also applies a negative potential pulse over conductor I to the grid of tube 8 in the sweep circuit of Fig. 4'to cause that circuit to recycle and to again apply a maximum potential to conductor 9 which, as before mentioned is connected to the deflecting plates'of both the cathode-ray tubes of Fig. 2. At this time, however, tube CR2 is disabled due tothe negative potential on its control anode 20, and tube CR2 is enabled due to the fact that its control anode 22 is positive due to the fact that tube I1 is blocked. In view of this condition the beam of tube CR2 now starts stepping downward over its target row, in the'same manner as before described for tube CR2, in response to incoming pulses over conductor In. As soon as the'beam of tube CR2 impinges on its lowermost target, the previously described transfer-is repeated but in the reverse order, 1. e., the system restores to the original condition with CR2 enabled and CR2 disabled due to the so-called flip-flop operation of vacuum tubes I1 and'l8, i. e., the reduction of anode current in tube l8 and a corresponding increase in tube ll.

When the flip-flop arrangement of tubes l1 and I8 reverses its condition and the anode of one tube is reduced in potential and the other anode increased in potential, the increased potential is prevented from counteracting the negative impulse transmitted over the recycling conductor I5 by introduction of unidirectional devices 30 and 3| in conductors 2i and I9 which are so poled as to permit the passage of negative potential current only, positive potential current being blocked. This same result can be obtained without the'use of unidirectional devices by the proper choice of circuit constants to give the negative pulses much steeper wave fronts than the positive pulses have and apply the "pulses through differentiating circuits.

Fig. 3 shows a cathode-ray tube CR3 having a plurality of rows of target anodes (2 in the fig-- ure) together with thermionic means responsive to the deflection of the electron beam to the last target of a row to cause the beam to succesively sweep over the individual rows, one at a time, as long as control impulses are applied to the system over conductor In of Fig. 4.

As in the previously described embodiments of Figs; 1 and 2, the sweep of the beam is con trolled by the sweep circuit of Fig. 4. I

When potential is applied to a system com prising Figs. 3 and 4, it will be assumed that thermionic tube 23 becomes conducting and tube 24 is therefore not conducting. Due to this coridition, there will be a negative potential on deflecting plate 25 of cathode-ray tube CR3 Whose function is to deflect the beam from row to row as it reaches the bottom or end of its step-bystep sweep, and consequently, deflecting plates 25 will be ineffective at this time and the beam will be directed to and impinge on the firstor to target of the first or left-hand row.

The tubes of Fig. 4 function at this time in the manner previously described to first apply a maximum potential over conductor 9 to the deflecting plates 26 and to successively cause the beam to step downward over the target of the left-hand row until the bottom target is reached whereupon a negative potential is applied to the grid of conducting tube 23 thus causing the tubes to reverse their conducting condition, i. e., to cause 24 to conduct and cause tube 23 to stop conducting. When the potential on the plate of This decrease in potential tube 24 is decreased due to the lowered resistance of its anode-cathode circuit, negative potential is applied over the recycling conductor 15 to the grid of tube 8 (F ig. 4) to cause the sweep circuit to recycle, as previously described, and cause a maximum'deflecting potential to be again applied over conductor 9 to the deflecting plates 26. At this time due to the increased potential on the anode of tube 23, deflecting plates 25 are increased in potential by an amount suflicient to cause the beam to be deflected at right-angles' to its sweep direction to impinge on the next or right-hand row of targets, over which row the movement of the beam will now be deflected" downward step-by-step under control of the sweep circuit of Fig. 4.

When the beam impinges on the bottom terf minal of the second or right-hand row the grid of tube 24 is driven negative thus stopping its flow of plate current and raising the potential on its anode thereby driving the grid of tube 23 positive and operating that tube to conduct again and descreasing'the potential on its anode which in turn decreases the potential in control anode 25 to allow the electron beam to revert back'to recyclingconductor IS in order to permit a high 7 positive potential on the anode of one tube from counteracting the negative recycling impulse applied to conductor [5 from the anodeof the other tube. As previously mentioned in connection with Fig. 2 these unidirectional devices can be eliminated by proper choice of circuit "constants.

What is claimed is:

1. In an electronic switching circuit, a' source of alternating current, cathode ray means com prising a plurality of discrete target anodes, said means being adapted to direct an electronic beam on each of saidanodes in progressive step-by-step succession, means energized and controlled by said alternating current to'produce an electrical potential which is reduced in substantially equal steps to control the progressive movement of said beam, and other means responsive to a beam impinging on certainof said anodes to cause said anodes to be cyclically retraversed by 'a beam during production of said electrical potential.

2. In an electronic switching circuit, a cathoderay apparaus having a series of discrete target anodes, means under the control of an alternating current applied thereto for producing an electrical potential which is reduced in substantially equal steps for deflecting a cathode-ray beam step-by-step to successively impinge on the individual anodes of said series, and other means responsive to a beam impinging on the last anode of said series to cause said apparatus to continuously recycle during application of said alternating current.

3. In an electronic switching circuit, a cathoderay device, having means for producing an electrical potential which is reduced in substantially equal steps for moving a cathode-ray beam successively, in a step-by-step manner over a plurality of targets, said targets being arranged in one or more groups and means responsive to the The reduction of po-' 

